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Thread: Shooting the Phase 4150 at F9

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    Shooting the Phase 4150 at F9

    For me, the good old days of f11 and forget it are gone with the 4150. F11 is an image destroying aperture that I will never use again. This limits the movements of most of my lenses which isn't that big of a deal for me since I always did limit my movements. I'll probably due away with shifting horizontally since I can just crop to create a 16X9 file or just pan a little for landscape images. Rise at f9 is usable to 10mm with all of my lenses except the 35XL.

    The incredible diffraction damage at f11 is easily visible when comparing the same image shot at f8 or f9. Visually, to me, the difference is staggering. In fact I can get the same type of image degradation if I shoot my Sony A7RIV at f11. It's just amazing how the Sony at f11 mimics the Phase at f11 with an image that has lost all of its micro contrast and detail. And.... that detail will never come back with any software. Those two sensors are different only in size so it's very understandable that they would have very similar characteristics.

    Of course my Rody 90 can easily be shot at f8 or even f5.6 with all sorts of movements but that's just one lens out of many. The only other Rody lens that may equal the 90 is the 138. So, that's two lenses that are comfortable on the 4150 at f8 with movements. I don't own the wider Rody lenses which may or may not perform well at f8 or f9 with movements.

    Regards....

    Victor
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    Re: Shooting the Phase 4150 at F9

    Quote Originally Posted by vjbelle View Post
    For me, the good old days of f11 and forget it are gone with the 4150. F11 is an image destroying aperture that I will never use again.
    Regards....

    Victor
    Interesting. I've shot with the IQ4 since we purchased one in December of 2018. I've been using F11 consistently with the Rode32, Rode40, Rode70, SK120 ASP and they are are all excellent at F11 even with massive enlargements and viewed at 300%. At F16 its a different story with noticeable diffraction beginning to rear its head. After extensive testing all of the above lenses shot with a object level target the sweet spot is F8-F11 consistently. YMMV.


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    Re: Shooting the Phase 4150 at F9

    The awakening for me was when I compared two images - one shot at f9 and the other f11. To me, the difference was enough to make me an f9 convert. Shooting with the Rody 90 does not mitigate the diffraction issue. The same image dulling characteristics are still there at f11. At f8 there is a dramatic change to the better.

    As always YMMV...

    Victor

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    Re: Shooting the Phase 4150 at F9

    I think there is already a big difference between f5,6 and f8. This gets worse by f11, however, when printed at 100x100 for example the difference isnít really visible. So for me I donít care, I even shoot at f16 if itís really needed and the images hold still more detail as my IQ3100.
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    Re: Shooting the Phase 4150 at F9

    I've been amazed for years by people saying they shoot at F11 and think they are getting the best from their lens/back.
    with old film era lenses, maybe it's moot, but a good modern digital era lens: it's night and day - diffraction is that bad!

    If you have to shoot at f11, then you have to. If you don't then, you are much better at f8.

    f5.6 is better at the center, but the edges/ corners are poor, (may not matter for a portrait...) but they do come in at f8, after that the trade off is not worth it.

    Again: this assumes you are using a top level digital lens. If not, then carry on as you were!

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    Re: Shooting the Phase 4150 at F9

    And again the question arises, why are sensor makers only going for more and more mp, there are sure other ways of improving iq without squeezing more mp in.

    I definitely would welcome a fullframe back in the 20ish mp range with the latest advances and zero noise iq, and i know i am not alone.

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    Re: Shooting the Phase 4150 at F9

    Quote Originally Posted by drevil View Post
    And again the question arises, why are sensor makers only going for more and more mp, there are sure other ways of improving iq without squeezing more mp in.

    I definitely would welcome a fullframe back in the 20ish mp range with the latest advances and zero noise iq, and i know i am not alone.
    Imagine - a 22MP full frame medium format 6x6 back for v-mount with real live view - or even a 645 mirrorless 22mp camera would be such stellar color and low light performer.

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    Re: Shooting the Phase 4150 at F9

    Quote Originally Posted by narikin View Post
    I've been amazed for years by people saying they shoot at F11 and think they are getting the best from their lens/back.
    with old film era lenses, maybe it's moot, but a good modern digital era lens: it's night and day - diffraction is that bad!

    If you have to shoot at f11, then you have to. If you don't then, you are much better at f8.

    f5.6 is better at the center, but the edges/ corners are poor, (may not matter for a portrait...) but they do come in at f8, after that the trade off is not worth it.

    Again: this assumes you are using a top level digital lens. If not, then carry on as you were!
    Mr. Narkin, I see bold statements that appear to be opinion vs scientific analysis so I'm curious about the parameters for your testing and assessment?
    The extensive testing I've done with the IQ4, Rode and SK lenses with an object level convergent target conclusively suggest otherwise that f8 is the Holiest of Grails.
    Even with a 32mm Rode F8 has somewhat limited DOF. Another important issue is taking an esthetic interesting image which always comes before 5% diffraction issues.

    Robert B

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    Re: Shooting the Phase 4150 at F9

    The difference in F8 vs F11 in DOF or F8 and F11 in diffraction, I will always go with DOF. The amount of diffraction to me is nominal, and most can be handled in C1 and post sharpening. For me just the thought of focus bracketing, in the field with tech camera, pushes me right back to taking a bit of diffraction. I have yet to find anyone who can notice in a print but I may have a more limited audience. The difference in DOF IMO is significant, and tilt will help, but again depending on subject matter as much more than 1 degree on an Arca camera will strongly effect the top of the shot adversely.

    Focus bracketing with auto stepping with the XF is fine but even then if there is any wind, then no toolset I know of can combine the files without aliasing. (trees and leaves moving etc.). When I have the right conditions that will allow focus bracketing and I have the right gear, I will always at least attempt it.

    I guess in summary, I have yet to have any real issues with diffraction at F11 on the IQ4, with either the XF and Phase glass or Arca and Rodenstocks. I rarely shift now so all my results are center shots. (prefer to pan).

    Paul C
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    Re: Shooting the Phase 4150 at F9

    There are wildly different opinions being expressed here regarding the maximum aperture number prior to diffraction being problematic. All of them are correct. That's because the definition of "problematic" is a subjective decision.

    Personally I've been shooting a lot of IQ4 150mp images at f/12 or so, which is my personal threshold for when diffraction becomes problematic. But whenever a client asks I tell them to either do their own testing (preferred) or that we'll send them an aperture-bracket series of raw files for them to make up their own evaluation. I emphasize that I believe the appropriate way to do such an evaluation is to use the raws in a real-world way. That is, if you make 1 meter prints, make a few 1-meter prints (or test strips scaled to replicate that size). If you display on the web, then display on the web.

    What is visible at 400% on screen, what is visible at 100% on screen, what is visible at zoom-to-fit, and what is visible in a given size print (on a given medium with a given printer) are all different.

    So while I don't subscribe to Victor's interpretation for my own work and my needs, I fully respect that it is accurate for his.

    The only thing two things I object to here are:
    1) The use of the phrase "image destroying aperture" which I think is a bit hyperbolic phrasing. But anyway, this is only a style-of-communication thing.
    2) "Those two sensors are different only in size" which is not accurate (at least as you've worded it); they are similar generation sensors made by the same manufacturer, but that does not mean (at all) that size is the only difference between them. I assume you mean more that "the two sensors have a similar pixel pitch and similar designs, so should respond to diffraction very similarly" which is accurate.
    Doug Peterson , Digital Transitions | Email
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    Re: Shooting the Phase 4150 at F9

    I'm probably wrong but... It's been my understanding that diffraction is more a function of the actual diaphragm opening size rather then the f/ratio. If that's the case then diffraction should be more problematic with shorter focal length lenses where the same f/ratio will correspond to a smaller opening.

    I just ran a quick and dirty test with both a 35mm blue ring and 150mm. Viewing results at 100% it appeared to me that diffraction jumped up on the 150mm between f/16 and f/22 which corresponds to a opening of 6.8mm (150/22) (though it increased slightly throughout the f/stop range). On the 35mm it appeared to jump between f/4 and f/5.6 for an opening of 6.25mm. The seems consistent with my understanding that it's more of a function of actual diameter of the opening rather than the ratio.

    I'm sure it's actually much more complicated than that. For now though I'll be more cautious about small apertures with shorter focal lengths.
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    Re: Shooting the Phase 4150 at F9

    Craig, I have found exactly the same thing. Diffraction, it seems to me, is a function of size of the opening, not the ratio to focal length.. I used to shoot "Full Plates" routinely at f64 (a whole school of photography did that!) and diffraction was not an issue. The lenses of course were 6 or 10 inches or more focal length.

    I'm by no means a physicist but I believe that the amount light bends around a diaphragm is almost irrelevant when the volume of light is high. It becomes more and more relevant as that same bending (which is a constant) becomes a large proportion of small volume - i.e. a small aperture.

    Just my amateur 2 cents worth...

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    Re: Shooting the Phase 4150 at F9

    Craig,

    The apertures may both be 6mm, but on the 150mm lens, that small opening is much further from the sensor and the diffracted light has had a longer distance in which to spread. That's why the f-ratio determines the aperture limited resolution. With any given lens, the optimal aperture is where the increase of quality from smaller aberrations crosses the decrease in quality from growing diffraction. It is VERY lens dependent.

    Bill,

    The diffraction is much greater at f/64. But you do much less magnification with a large plate/film. Making a 16x20 print from an 8x10 negative can tolerate a LOT of diffraction softening.

    Best,

    Matt
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    Re: Shooting the Phase 4150 at F9

    Call me a Luddite but I’m more interested in the beauty of the photograph vs the n’th degree of sharpness / diffraction etc etc.

    it’s hard enough with the IQ4150 to get decent DoF without resorting to tilt at f/8 or f/11 imho. But ultimately the print on the wall is all that matters, not 400% in Capture One.
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    Re: Shooting the Phase 4150 at F9

    Diffraction is proportional to the f-number as that is related to the image plane. (Whereas resolution of the object plane is proportional to the entrance pupil. This is recognized in microscopy where microscope objectives are given a numeric aperture which is related to resolving power at the sample plane.) The beauty for f-numbers for photographers is that effect of diffraction is the same at a particular aperture, regardless of focal length. But diffraction happens at any aperture--images are diffraction patterns.

    The diffraction we are talking about is whether the image is perceived as sharp. That is proportional to the viewing distance and the permissible circle of confusion, which is related to format size (but not resolution). The problem is that as pixel resolution increases, the viewing distance at 100% decreases. So we are viewing images at viewing distances (assuming you are not cropping to that scale) that are unrealistic. Diffraction is really proportional to format, which is why as the format size increases, the maximum aperture is smaller--this is why 8x10 lenses stop down to f/64 and 35mm f/22.

    Depth of field is an important quality in an image. I don't understand the limitation of sticking to the "sharpest" aperture if it does not give me the DoF I want. While the focal plane can soften at small aperture, the areas in front and behind that plane do get sharper and more detailed--the advantage of depth of field. This is not a zero sum game. (And another myth is that you lose pixel resolution: you don't, diffraction does not reduce pixel resolution.)

    My advice, print the image and look at it. I routinely use f/16 and sometimes f/22 with my 40MP MFD back and there is no softness in any of my images printed at 40"+. Having more pixels do not change that. (Likewise, if you had a lens that you like on a smaller resolution sensor, it will not actually make softer images on a higher resolution sensor even if you see softness at 100%.) In order to evaluate sharpness, you need to view the image at normal viewing distances. And perception of an image is not a comparative problem--an image must look inherently sharp, not sharp in reference to another image.

    Technical quality for technical quality's sake is a tyrant. (No one will think less of your work because the effects of diffraction can be seen in the file at 100%.)

    (I kind of miss the film days when "huge" prints were 16x20 and you looked at negatives with a 6x loupe. We thought our images and optics were sharp then...)
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    Re: Shooting the Phase 4150 at F9

    Quote Originally Posted by GrahamWelland View Post
    Call me a Luddite but Iím more interested in the beauty of the photograph vs the níth degree of sharpness / diffraction etc etc.

    itís hard enough with the IQ4150 to get decent DoF without resorting to tilt at f/8 or f/11 imho. But ultimately the print on the wall is all that matters, not 400% in Capture One.
    Graham,

    I think you're ignoring a few important use cases. 400% view is important if you're going to print a single frame over 36 feet wide for indoor viewing. Or if your viewing distance of a 2 meter print is 1"... with an 8x loupe.

    I suppose I'm happy to have essentially infinite resolution, i.e., I simply can't run out of pixels in an uncropped print.

    Matt

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    Re: Shooting the Phase 4150 at F9

    Quote Originally Posted by GrahamWelland View Post
    Call me a Luddite but I’m more interested in the beauty of the photograph vs the n’th degree of sharpness / diffraction etc etc.

    it’s hard enough with the IQ4150 to get decent DoF without resorting to tilt at f/8 or f/11 imho. But ultimately the print on the wall is all that matters, not 400% in Capture One.

    Thank you.

    PS: You must be a Luddite?


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